1. Field of the Invention
The present invention relates to a semiconductor memory technology, and in particular to a semiconductor device with a metal-insulator-metal capacitor structure in a semiconductor device and a method for fabricating the same.
2. Description of the Related Art
Semiconductor memory devices are commonly available in various forms, such as EPROMs, EEPROMs, flash memories, and DRAMs. Currently, DRAM is widely applied in large capacity memory technology. DRAM is typically a volatile memory consisting of a transistor and a capacitor. Digital signals are stored or erased by charging and discharging capacitor in the DRAM. Accordingly, improvement of the capacitor structure tends to be the direction in which semiconductor memory technology is developing.
In recent years, in order to satisfy demands for high density DRAM cells in a semiconductor chip, the size of the DRAM cell has been miniaturized. That is, the used space of the capacitor for conventional DRAM structure is reduced. More memory capacity is required, however, to accommodate large size computer software. There are several approaches to reduce the size of the capacitor while increasing memory capacity. For example, a high dielectric constant (K) material can be employed as a capacitor dielectric to increase the capacitance. Additionally, increasing the surface area of the capacitor in a limited space also can increase capacitance.